The purpose of this proposed study is to examine the generational transmission of early childhood precursors of young adult drug use. This longitudinal prospective study began in 1975 (T1), when first generation (G1) mothers assessed one of their children (ages 1-10) in terms of personality/behavior. Data were also obtained on family context and parent child-rearing variables. Eight years later (T2), when the G2 children were 9-18, mothers and children were reassessed, followed by a third and fourth data collections (T3/T4). At the T2/T3/T4 data collections, the original T1 measures were repeated, and additional data were gathered from both mother and child on personality/behavior, parent-child relations, and drug use. Having established with the T1-T4 data that childhood factors do influence later drug use, we farther investigated these influences by studying the 63 offspring of the 62 original study children. We already have data on 150 G3 children and their parents. The G3 children-will be evaluated at age 2 and at age 7 in terms of childhood precursors of later drug use. We will then trace the intra-and intergenerational pathways (T1-T5) to determine how drug- prone characteristics are transmitted. The hypothesized pathway, based on our Family Interactional Theory, is that parent personality risk characteristics (unconventionality, poor adjustment, poor control of emotions, and interpersonal difficulty) lead to parent-child mutual detachment (e.g., less warmth, more conflict). This then leads to the development in the child of risks for drug use. We hypothesize that this pathway, already shown in the G1 parent and G2 child, will be repeated for the G2 child (now a parent) and his/her G3 offspring. Also of interest is our proposed examination of risk (drug-conducive) and protective (nondrug-conducive) intra- and intergenerational interactions as they affect G3 child outcome. The sample size for the proposed study will be 250 2-year olds (50 per year) and both their parents (500), as well as 125 7-year-olds and their parents. T5 data will be collected using self-reports, test situations, and observational procedures. Only psychometrically sound scales will be used. The analytic techniques will include structural equation and hierarchical regression. The significance of the study lies in its delineation of generational factors implicated in the development of childhood precursors of drug use. By focusing on ways to improve the psychosocial environment of the young child at risk, one can not only lessen the likelihood of later drug use, but also effect changes that will "break the chain" of generational risk transmission.